[clang] [clang-tools-extra] [lldb] [llvm] [Support][JSON] Use `std::unordered_map` for object storage (PR #171230)

Wed Apr 22 16:47:57 PDT 2026

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-gcc-ubuntu-no-asserts` running on `doug-worker-6` while building `clang-tools-extra,clang,lldb,llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/202/builds/6434

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (build-unified-tree) failure: build (failure)
...
0.879 [7560/8/120] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/StringMap.cpp.o
0.902 [7559/8/121] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/StringSaver.cpp.o
0.925 [7558/8/122] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/StringRef.cpp.o
0.948 [7557/8/123] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/SuffixTreeNode.cpp.o
0.970 [7556/8/124] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/SuffixTree.cpp.o
0.991 [7555/8/125] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/SystemUtils.cpp.o
1.016 [7554/8/126] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/TarWriter.cpp.o
1.039 [7553/8/127] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/TextEncoding.cpp.o
1.067 [7552/8/128] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/ThreadPool.cpp.o
3.084 [7551/8/129] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/ARMAttributeParser.cpp.o
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/ARMAttributeParser.cpp.o 
/opt/ccache/bin/g++ -D_GLIBCXX_USE_CXX11_ABI=1 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbot/buildbot-root/gcc-no-asserts/build/lib/Support -I/home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/lib/Support -I/home/buildbot/buildbot-root/gcc-no-asserts/build/include -I/home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include -I/home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/../third-party/siphash/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-array-bounds -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -fno-exceptions -funwind-tables -fno-rtti -std=c++17 -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/ARMAttributeParser.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/ARMAttributeParser.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/ARMAttributeParser.cpp.o -c /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/lib/Support/ARMAttributeParser.cpp
In file included from /usr/include/c++/9/bits/stl_algobase.h:64,
                 from /usr/include/c++/9/bits/char_traits.h:39,
                 from /usr/include/c++/9/ios:40,
                 from /usr/include/c++/9/ostream:38,
                 from /usr/include/c++/9/iterator:64,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/ADT/ADL.h:13,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/ADT/Hashing.h:47,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/ADT/ArrayRef.h:12,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/Support/ELFAttributes.h:12,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/Support/ARMBuildAttributes.h:22,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/Support/ARMAttributeParser.h:12,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/lib/Support/ARMAttributeParser.cpp:9:
/usr/include/c++/9/bits/stl_pair.h: In instantiation of ‘struct std::pair<const llvm::json::ObjectKey, llvm::json::Value>’:
/usr/include/c++/9/ext/aligned_buffer.h:91:28:   required from ‘struct __gnu_cxx::__aligned_buffer<std::pair<const llvm::json::ObjectKey, llvm::json::Value> >’
/usr/include/c++/9/bits/hashtable_policy.h:233:43:   required from ‘struct std::__detail::_Hash_node_value_base<std::pair<const llvm::json::ObjectKey, llvm::json::Value> >’
/usr/include/c++/9/bits/hashtable_policy.h:264:12:   required from ‘struct std::__detail::_Hash_node<std::pair<const llvm::json::ObjectKey, llvm::json::Value>, true>’
/usr/include/c++/9/bits/hashtable_policy.h:2027:13:   required from ‘struct std::__detail::_Hashtable_alloc<std::allocator<std::__detail::_Hash_node<std::pair<const llvm::json::ObjectKey, llvm::json::Value>, true> > >’
/usr/include/c++/9/bits/hashtable.h:173:11:   required from ‘class std::_Hashtable<llvm::json::ObjectKey, std::pair<const llvm::json::ObjectKey, llvm::json::Value>, std::allocator<std::pair<const llvm::json::ObjectKey, llvm::json::Value> >, std::__detail::_Select1st, std::equal_to<llvm::json::ObjectKey>, llvm::json::Object::ObjectKeyHash, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, std::__detail::_Hashtable_traits<true, false, true> >’
/usr/include/c++/9/bits/unordered_map.h:105:18:   required from ‘class std::unordered_map<llvm::json::ObjectKey, llvm::json::Value, llvm::json::Object::ObjectKeyHash>’
/home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/Support/JSON.h:106:11:   required from here
/usr/include/c++/9/bits/stl_pair.h:214:11: error: ‘std::pair<_T1, _T2>::first’ has incomplete type
  214 |       _T1 first;                 /// @c first is a copy of the first object
      |           ^~~~~
In file included from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:21,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/lib/Support/ARMAttributeParser.cpp:13:
/home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/Support/JSON.h:93:7: note: forward declaration of ‘class llvm::json::ObjectKey’
   93 | class ObjectKey;
      |       ^~~~~~~~~
In file included from /usr/include/c++/9/bits/stl_algobase.h:64,
                 from /usr/include/c++/9/bits/char_traits.h:39,
                 from /usr/include/c++/9/ios:40,
                 from /usr/include/c++/9/ostream:38,
                 from /usr/include/c++/9/iterator:64,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/ADT/ADL.h:13,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/ADT/Hashing.h:47,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/ADT/ArrayRef.h:12,
                 from /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/llvm/include/llvm/Support/ELFAttributes.h:12,

```

</details>

https://github.com/llvm/llvm-project/pull/171230